#include <iostream>
#include <vector>
using namespace std;

class Solution 
{
public:
    int takeAttendance(vector<int>& nums) 
    {
        int left = 0, right = nums.size() - 1;
        while (left < right)
        {
            int mid = left + (right - left) / 2;
            if (nums[mid] == mid) left = mid + 1;
            else right = mid;
        }
        return nums[left] == left ? left + 1 : left;
    }
};

void Test01()
{
    vector<int> nums = { 0,1,2,3,5 };
    Solution s;
    cout << s.takeAttendance(nums);
}

int main()
{
    Test01();
    return 0;
}
